Control apparatus

ABSTRACT

A spring mounted transducer where the plane of the spring is perpendicular to the longitudinal axis of the transducer and is parallel to the direction of flexure of the transducer. The mounting of the spring is at the transducer centerline for greater efficiency and longer life and the spring in an optional embodiment has a reduced thickness flexing section at the centerline of the transducer along with an improved clamp for greater spring reliability.

United States Patent Royster [451 June 27, 1972 [54] CONTROL APPARATUS 3,341,721 9/1967 Vincent ..3l0/8.6 [72] Inventor: Larry H. Royster, Cary, NC. 3,360,664 12/1967 Straube ..3lO/9.1 X

[73] Assignee: Honeywell Inc., Minneapolis, Minn. Primary Examiner-J. D. Miller [22] Filed: May 1, 1969 Assistant Examiner-Mark O. Budd I Attorney-Charles J. Ungemach, Ronald T. Reilmg and [21] App]. No.: 820,927 Charles L. Rubow 52 us. CI ..310/8.6, 310/9.1 [57] ABSTRACT [51 1 ..H04r A pring mounted transducer where the plane of the spring is [58] Field of Search ..3 10/86, 9.1, 9.2, 9.4 perpendicular to the longitudinal axis f the transducer and is parallel to the direction of flexure of the transducer. The [56] References C'ted mounting of the spring is at the transducer centerline for UNITED STATES PATENTS greater efficiency and longer life and the spring in an optional, embodiment has a reduced thickness flexing section at the 3,093,760 I Tarasevich ..3 10/9. 1 ente -line of the transducer along with an improved clamp for 2 9 8/1965 greater spring reliability. 3,321,189 5/1967 3,328,610 6/1967 4 Claims, 6 Drawing Figures PR I O R A R T re usal T PATENTEDJUHZ'I I972 PRIOR ART FIG. 3

PRIOR ART FIG. 2

INVENTOR. LARRY H. ROYSTER BY flux/(4 ATTORNEY CONTROL APPARATUS THE. INVENTION The present invention relates generally to transducers and more specifically to bender bar transducers. In the past, the method of mounting transducers has varied over a wide range. In general for early spring hinge mounting configurations, the springs were mounted in parallel with the longitudinal axis of the bender bar transducer, and then as shown in a Gordon Vincent U.S. Pat. No. 3,341,721 issued Sept. 12, 1967 and assigned to the same assignee as the present invention, the spring hinges were mounted at right angles to the longitudinal axis. However, while this method of mounting provided increased efficiency over the prior systems, failure often occurred when using large bender bars. The failure resulted from over stressing the springs.

'The present invention overcomes the prior art problems in two ways which may be used separately or together. The first I is to clamp the springs so that they can flex from at the longitudinal axis of the transducer rather than only at locations outward from the edge of the transducer as shown in the Vincent patent, and the other is to reduce the thickness of the spring hinges atthe desired flexure point along with providing clamps which extend past the edge of the reduced section so that there are no concentrated stresses on the springs at the edges of the clamps. The concentrated stresses were found to occur even though the clamps were rounded at the comers. The present method of clamping substantially reduces this type of stress.

It is therefore an object of the present invention to increase the efficiency of a spring mounted bender bar transducer. Other objects and advantages of the'present invention will be apparent from the reading of the specification and appended claims in conjunction with the drawings wherein:

FIG. 1 is a side view of a spring mounted transducer;

FIG. 2 is a front view perpendicular to the longitudinal plane of the transducer showing its general shape and method of clamping;

FIG. 3 is a detail view of the clamping portion along with the reduced section spring;

FIG. 4 shows the prior art clamp;

FIG. 5 is a schematic illustration of the bending mode produced in the prior art spring mounts; and

FIG. 6 is an illustration of the bending mode produced in the spring mount of-the present invention.

' In FIG. I a bending bar transducer generally indicated as 10 i is shown adjacent a support'l2 and connected thereto by springs 14 and l6.'The springs 14 and Marc clamped against the support 12 by segmented portions 18 and 20 respectively. The support 12 may be part of a housing or any other stationary object with respect to which the transducer 10 is to vibrate. The transducer 10 has bolts 22 extending therethrough and compressing the transducer elements between clamps 32 and 34 in a manner known in the art and described in the abovereferenced Vincent patent. On each end of the transducer 10 are additional bolts 24 and 26 compressing clamps 28 and 30 respectively against mating portions on clamps 32 and 34. Bolts 24 and 26 extend through holes in the clamps 28 and 30 and the springs 14 and ,16 to hold the springs in place. As shown more clearly in FIG. 2 springs 14 and 16 are clamped securely against raised shoulders on clamps 32 and 34 which are used to hold the transducer 10 in a compressed state. The clamping of the springs 14 and 16 at the support end is shown schematically as there are many ways of accomplishing the clamping not pertinent to the invention.

' As will be ascertained the same numbers utilized in FIG. 1 are again used in FIG. 2.

In FIGLB a bolt 41 is shown with its head against an upper clamp 43 holding one end 45 of a flexible spring generally designated as 47 against a lower portion 49 of the clamping mechanism. Only a section of portion 49 is shown. The spring 47 and the clamps have holes therein through which the bolt 41 passes to produce the clamping or compressing action. The

spring 47 also has a right hand portion 51 and a reduced thickness section 53. The reduced section 53 extends from a short distance interior of the edge of clamps 43 and 49 to a short outside the edge. Upon flexing of the clamped portion, the primary flexing will occur in the reduced section 53 and somewhere near the middle thereof if the end 51 is kept stationary.

In FIG. 4 a further clamp is shown comprising a spring hinge or flexure means 56 clamped between clamping portions 58 and 60 by a bolt 62. As will'be noted, the right hand side of clamps 58 and 60 are rounded as in the prior'art to reduce stress in the spring 56. While this arrangement is better than square comers for reducing stress in spring 56, there is still a substantial amount of stress at the contacting edges since movement of the clamp relative to a stationary support to which the right hand portion of spring 56 is fixed will create most of the stress at the contact points.

The stress is substantially reduced by the configuration shown in FIG. 3. Both methods of clamping described above will work with the apparatus shown in FIG. 1. However, the chances of breaking the spring hinge from clamping stresses is substantially reduced with the embodiment shown in FIG. 3.

FIG. 5 illustrates how the springs are bent when they are clamped as shown in the above-referenced Vincent patent. The dashed lines show a bender bar 65 in a relaxed or nonoperating condition while solid lines show the bender bar, which is numbered 65 under maximum deflection in an operative mode. A spring at one end is designated 67 in the unbent or relaxed condition and 67' in the operative condition of maximum deflection. It will be noted that there is substantial bending of the spring due to the fact that there is a significant distance from the longitudinal axis 69 to the edge of bar 65'.

In FIG. 6 a portion of the drawing of FIG.. 5 is reproduced using 71 and 71' to identify the bender bar, 73 to identify the spring and 75 to identify the longitudinal axis of the bender bar 71. It will be noted that since the end of transducer 71 moves much less at its center line than at its edge, there will be considerably less bending induced in the spring 73 than occurs in spring 67. Thus, the spring is able to support the bender bar 71, without being over stressed, for considerably greater deflections of the bender bar than in the prior art method of mounting.

Since the bending stresses in the springs are reduced with the method of mounting shown in FIGS. 1, 2 and 6, less energy is used to bend the springs and thus the total system operation is considerably more eflicient.

In summary therefore the present invention pertains both to an improved method of mounting a spring hinge supported transducer so that the springs can flex at the longitudinal axis of the transducer, and to an improved configuration of the flat spring hinge or flexure wherein the clamping stresses are reduced to provide for greater reliability.

It will be apparent to those skilled in the art that many modifications of the apparatus may be made without going beyond the scope of the appended claims wherein I claim:

1. In combination with transducing apparatus of the type I wherein a transducing element deflectable in a direction perpendicular to a central longitudinal axis thereof is supported at opposite ends by flat springs positioned generally perpendicular to the axis, each spring extending to a mount on a housing, the axis lying in a plane perpendicular to the direction of deflection, the improvement which comprises:

clamping means for attaching the springs to the transducing element, said clamping means engaging the Springs only on the side of the plane opposite the mounts therefor. 2. The apparatus of claim 1 wherein: each spring includes an area of reduced thickness adjacent its intersection with the plane. 3. The apparatus of claim 1 wherein said clamping means includes: a member interposed between each spring and the transducing element;

means for affixing said member to the transducing element; clamping plate and the portion of said member in engagen ment with the spring lying only on the side of the plane means for affix ng the spnng to said member so that it conopposite the mount f the Spring i clamping plate new the spnng only on the of the plane opposne of and said member having surfaces lying substantially in the the mount therefor. plane; and apparatus ofFlalm 3 wherein: I the spring includes an area of reduced thickness adjacent its said means for affixing the spring to said member comprises intersection with the plane.

a clamping plate and means for clamping a portion of the spring between said clamping plate and said member, said 

1. In combination with transducing apparatus of the type wherein a transducing element deflectable in a direction perpendicular to a central longitudinal axis thereof is supported at opposite ends by flat springs positioned generally perpendicular to the axis, each spring extending to a mount on a housing, the axis lying in a plane perpendicular to the direction of deflection, the improvement which comprises: clamping means for attaching the springs to the transducing element, said clamping means engaging the springs only on the side of the plane opposite the mounts therefor.
 2. The apparatus of claim 1 wherein: each spring includes an area of reduced thickness adjacent its intersection with the plane.
 3. The apparatus of claim 1 wherein said clamping means includes: a member interposed between each spring and the transducing element; means for affixing said member to the transducing element; and means for affixing the spring to said member so that it contacts the spring only on the side of the plane opposite of the mount therefor.
 4. The apparatus of claim 3 wherein: said means for affixing the spring to said member comprises a clamping plate and means for clamping a portion of the spring between said clamping plate and said member, said clamping plate and the portion of said member in engagement with the spring lying only on the side of the plane opposite the mount for the spring, said clamping plate and said member having surfaces lying substantially in the plane; and the spring includes an area of reduced thickness adjacent its intersection with the plane. 